In this lesson, we revisit Warren Buffett’s four rules for investing in stocks. These rules are that the stock must be managed by vigilant leaders, have long-term prospects, be stable and understandable, and undervalued. All four of these rules must be met in order for Buffett to invest in a stock. The next few lessons will focus on each of these rules in turn, exploring how Buffett executes them. The first of these will be understanding how a stock must be managed by vigilant leaders. Remember that all four rules must be met for Buffett to invest in a stock.